Try to google german word ¨oktavgitarre¨, e.g. stollguitars had their model 1600€.
Esteve makes an octav guitar too
What is an octave guitar?
As the name says: a guitar tuned an octav up with string length ca. 40 cm.
It has often been used in music school guitar orchestras and together with acoustic bass guitars they give more depth and top to the sound.
Guitar orchestra with octave guitar, ¨normal¨guitars and bass guitars has been called ¨the german model¨. ¨Japanese model¨is when you include all transposing guitars in the orchestra(german model + 3th up, 5th up).